Spark plug gapping machine



Dec. 29, ODEN SR SPARK PLUG GAPPING MACHINE Filed Nov. 21, 1950 8 Sheets-Shoat l Q w, a

LEWIS M. ODEN, SR.

Dec. 29, 1953 Filed Nov. 21, 1950 8 Sheets-Sheet 2 L. M. ODEN, SR 2,664,135

SPARK PLUG GAPPING MACHINE LEwIs' M. ODEN, SR.

Dec. 29, 1953 QDEN, 5 2,664,135

SPARK PLUG GAPPING MACHINE Filed Nov. 21, 1950 8 Sheets-Sheet 3 LEWIS M. ODEN, 3R.

Dec. 29, 1953 L. M. ODEN, SR 2,664,

SPARK PLUG GAPPING MACHINE Filed No v. 21, 1950 8 Sheets-Sheet 4 gwuem tom LEWIS M. ODEN, SR.

Dec. 29, 1953 QDEN, 5 I 2,664,135.

SPARK PLUG GAPPING MACHINE Filed Nov. 21, 1950 8Sheets-Sheet 5 gvwmvfo'v LEWIS M. ODEN, SR.

Dec. 29, 1953 Filed Nov. 21, 1950 L. M. ODEN, SR

SPARK PLUG GAPPING MACHINE 8 Sheets-Sheet 6 LEWIS M.ODEN,SR.'

Dec. 29, 1953 M. ODEN, SR

SPARK PLUG GAPPING MACHINE 8 Sheets-Sheet 8 Filed NOV. 21, 1950 FIG.

gwuwwfm LEWIS M.ODEN,SR.

FIG. l2

Patented Dec. 29, 1953 UNITED STATES PATENT OFFICE (Granted under Title 35, U. S. Code (1952),

see. 266) Claims.

The present invention relates generally to tools and specifically to spark plug gap setting tools.

This application is a continuation in part of my copending application Serial No. 552,113, filed August 31, 1944, now Patent No. 2,481,530, granted September 13, 1949, and has for its principal object the provision of an improved tool by which the gap between the central and the shell electrodes of a spark plug can be gauged simultaneously with the bending of the grounded electrodes to the position whereby the gap formed between the electrodes is that found to result in the optimum efficiency of the internal combustion engine in which the spark plug is used.

Another object of the invention is to provide an improved tool for use on spark plugs of the type used in aviation engines wherein the forming of the electrode surfaces of the grounded or shell electrodes and the final adjustment of the gap between the electrodes is accomplished in a single operation of the tool without the imposition of any bendin moment to the central electrode of the plug.

Another object of the invention is to provide an improved tool wherein two or more grounded or shell electrodes of a spark plug can be simultaneously adjusted with respect to the central or insulated electrode.

A further object of the invention is to provide an improved tool wherein the spark plug is universally mounted to facilitate proper alignment thereof prior to and during the operation of the tool.

Other objects and advantages of the invention will be in part evident to those skilled in the art,

and in part pointed out hereinafter in the following description taken in connection with the accompanying drawings wherein there is shown by way of illustration and not limitation preferred embodiments thereof.

Figure 1 is a view showing the invention in side elevation.

Figure 2 is a front elevational view thereof.

Figure 3 is a view in side elevation with parts broken away to better illustrate the operation of the tool.

Figure 4 is a horizontal sectional view taken on the line 4-4 of Figure 3.

Figure 5 is an enlarged detail view, partly broken away on the line 5-5 of Figure 4, to better illustrate the gapping operation of the tool.

Figure 6 is an enlarged sectional view of the feeler gauge chuck assembly.

Figure 7 is a detailed view of the vice block associated with the feeler gauge chuck.

Figure 8 is a dctail view of one of the chuck jaws.

Figure 9 is a side elevational view with part broken away showing a modified form of the tool and cylinder block.

Figure 10 is a detail front elevational view partly broken away of the cylinder block assembly shown in Figure 9.

Figure 11 is a bottom view of the cylinder block shown in Figure 10, and,

Figure 12 is an enlarged detail sectional view of a modified form of spark plug adapter.

Referring to the drawings in detail, in Figures 1, 2 and 3 the reference character A indicates generally my improved spark plug gapping tool, which comprises a main frame or arbor I!) having spaced upper and lower jaws II and I2 respectively and a base l3. Said base is is provided with bosses l4 and I5 which are bored to receive bolts It by means of which the tool can be fastened to any suitable support.

The upper jaw II is provided with two spaced parallel bores l8 and IS. A plunger 20 having rack teeth 2| formed thereon is slidably mounted within the bore l8. A shaft 22 having a pinion 23 formed thereon is journalled in a bore 24 formed in and extending transversely through the upper jaw H. Pinion teeth 23 engage with the teeth of the rack 2|. The shaft 22 is retained within the bore 2-4 by means of a washer 26 fixed to the end of the shaft 22 by means of a screw 21.

The plunger 20 is provided with a central bore 28 into the lower end of which is slidably mounted a stud 29 formed integral with and extending upwardly from an adapter block 30 having a bore 3| formed therein.

A feeler gauge chuck assembly C, similar to the well-known Jacobs chuck used extensively in machine shops is rotatably mounted to the underside of said adapter blockby means of stud 32 secured within the bore 3| in said adapter block by means of set screw 33.

The chuck assembly C as shown in Figure 6 comprises a main body portion 34 having a groove 35 formed therein to accommodate a split nut 36. A sleeve 31 having gear teeth 38 formed in the lower end thereof isrotatably mounted over the body portion 34 of said chuck and is fixed in any suitable manner to the split nut 36. The body 34 is further provided with three diverging bores 39, in each of which is slidably mounted a chuck jaw 40.. Said chuck jaws 40 are provided with threads 42 adapted to engage the threads of the split nut 36, whereby rotation of said nut will cause the chuck jaws 40 to move upwardly or downwardly in their respective bores depending on the direction of rotation of said sleeve nut. The chuck jaws at are provided with a cutaway portion 44 to form a seat 44a upon which rests the head 45 of a spring-pressed vice block 56. Said vice block 46 is disposed centrally of the body 34 beneath "its lower wall 4'! and comprises a triangular shaped shank iii which depends between the flat vertical faces 49 of the chuck jaws 40. The flat faces 50 of the shank are aligned with the vertical faces 49 of the chuck jawsv 4S, and together provide a simple effective vice be tween which the feelers 53 are clamped.

A portion of the head 45 of the vice block At is thickened as at to cause the one feeler 54 to extend below the lower end of the, feelers 53, the purpose of which is to, facilitate the insertion of the feelers within the gap between the centrrl and shell electrodes of the spark plug. The blade portion of said feelers is chamf ered along its edges to insureagainst kick-back of thegrounded or shell electrodes during gapping operation and is-also shaped to conform to the radius of the central electrode of the particular type of spark plug to be gapped. r r

' A coil spring l-is locc ted within the bore 28 of the plunger 2:: and extends between the upper face of the stud 29 and the shoulder 53 of the bore 28 at the point of reduced diameter of the bore. The stud 29 is adjustably held within the bore 28 against the pressure of the spring 5? by means of an elongated bolt 59, the head 60 thereof resting upon the upper surface of the plunger 2!! and its lower end I32 threaded into the tapped bore I53 in the stud 29.

It will be noted from the description, and with reference to Figure 3 of the drawings, the operator can accurately adjust the feeler-gauge chuck assembly C and consequently the feeler gauges 53 with respect to the lower jaw I2 of the tool to accommodate for spark plugs of varying lengths.

A push-rod, adapted to reciprocate within the'bore I6 in unison with the plunger 28 is connected thereto by means of yoke 68. One end of said yoke is fitted over the reduced end 59 of the plunger'2ll rnd'is held thereon by means of a taperedpin I0. The opposite end thereof is bored and tapped, to receive an adjustable bushinglll having a bore through which the pushrod 61 passes. Said push-rod is adjustably fixed therein by means of'set-screws 12.

A' guide member I3 having a central bore M through'which passes the lower end of the push- 'rod 61' is'fitted into the upper end of the bore I8.

and its upper member I6 are hinged together as at I9. The lower member 18 is in turn connected to the stem 80 of the piston 8| mounted in the fluid pump 82 by means ,of lost motion connection 83." In'the present instance a pin and slot connection is shown, but any well-known type of lost-motion connection can be utilized for the purpose.

A compression spring 84 is provided to hold plunger 20 and the push-rod fi'i up in inoperative position and is mounted by having the upper face of the guide member I3 form a seat for the lower end of the spring 84 which as shown surrounds the push-rod 61 and extends upwardly between the upper jaw II of the main frame IE3 and the .underside of the yoke 68. The upper end of the spring seats in a bored washer BI which bears 4 against the lower end of the adjustable bushing I. As shown, the spring 84 can be readil adjusted to vary the action of the tool by means of the bushing "II.

The fluid pump 82 comprises a casting 85 having a cylinder 86, a piston 8I reciprocatably mounted within said cylinder, and bonnet 81. The bonnet 87 is screw threaded as at 88 into the casting 85, said bonnet being centrally bored to allow the stem 88 of the piston 8| to pass therethrough. The casting 85 i in turn screw threaded into the tapped bore 89 formed in the ram block 90. Said ram block 9!! is secured in place upon the upper surface of the lower jaw I2 of the main frame I0 by means of bolts 9I.

As shown in Figure 4, the ram block 90 has formed therein three equi-angularly spaced horizontally disposed bores 92, 93 and 94 into which are fitted pistons 95,36 and 91, respectively. The pistons and 9] are fitted with gapping rams 58, S9 and ltd, respectively the end of which are machined as at IIlI to form electrode shaping dies. Said rams extend inwardly through the bores Hi2, H13 and IE4 into the opening I55 formed in the front portion of the ram block 90.

Springs it! and IE8 are positioned between the inner ends of the bores 92, 93 and 94 and the inner faces of the pistons 95, 95 and 91, and are adapted to retain said pistons and rams in their retracted position until influenced by the fluid pump 82. The bores 93 and 94 are connected to the bore 22 by mean of fluid passages ii t iii' and iii-I2 respectively. The'bore 92 is in direct communication with the fluid pump The outer ends of bores 92, 93 and M are sealed by means of plugs H3, H4 and H5 spectively, said plugs being bored and tapped receive adjustable stops IIB, II! and H3 adapted to limit the outward movement of the pistons 95, 96 and 9'1 after the pressure on said pistons ha been released.

As shown in Fig. 3 screws HQ with a dog point are threaded in the ram block so and are re to 5 adapted to coact with the slotted portions I20 of the rains 98, Q9 and I!!!) so as to hold in alignment the radii or die ends of rams with respect to the outer electrodes of the spark plug to be gapped. Screws 552 are not used to stop the inward travel 0;" e rams 98, 99 and IE0. Stop screw I3? (see 3) is used to limit the travel of rams 99 and It!!! inwardly so that no damage may be done to the chuck jaws of rams when no spark plug is in the machine to catch the travel of the rams.

The lower jaw I2 projects beyond the front of the main frame It to provide a bifurcated support I23 containing a spark plug I32 during gapping operation of said tool. Said bifurcation is alignment with the opening I05 in the ram block 38 and that portion of the underside of block adjacent the opening I05 is machined to form a recess I24 into which the radial flange 1'15 of the spark plug adapter I25 loosely fits when the adapter i positioned upon the support 523. In operation the adjustable spark plug adapter 26 abuts the adjustable stop I33 positionecl at the root of the bifurcated support I23 wien in proper alignment with the feeler gauges The spark plug adapter I26 comprises an internally threaded body I28, which is provided at its top with the annular flange I25. An adjustable nipple I29 is threaded into the body I28 and is retained therein by means of a jam nut I30. Said nipple I29 is further provided with an extending annular flange I3I upon which rests the shell hex of the spark plug I32. The harness end of the spark plug extends downwardly through the nipple I29 and its electrode end extends upwardly into the opening I05 in the block 99 between the rams 99, 99 and I00 as shown in Figure 5. It is intended that the spark plug I32 fit loosely in the adapter I26 and the adapter fit loosely between the bifurcated support I23 with its annular flange I25 resting upon the ledge I21 of said support so that the spark plug can be easily shifted and aligned with the feelers 53 and the rams 98, 99 and I00 before the gapping operation of said tool is begun.

As shown in Figure 5, the chuck assembly 0 and the feeler gauges 53 have been moved downwardly into the gapping position with the spark plug I32 mounted in the body I28 with the flange I25 resting upon the ledge I21 of the support I23. The rams 98, 99 and I00 as shown are about to be moved inwardly under the pressure of the pump 82 towards the central insulated electrode of the plug to thereby bend the shell electrodes towards the central electrode to clamp the feeler gauges 53 therebetween. I

In ordinary use, a large number of spark plugs of the same make are gapped at one time. If a different lot of another type of plugs is to be gapped, for example, two or four electrode plugs, the ram block 98 can be readily replaced by another type of cylinder block, such as that shown in Figures 9, and 11.

The operation of the tool is as follows: After the spark plug I32 has been placed within its adapter I25 and said adapter positioned in the tool, plunger 2:: and the chuck assembly C are lowered by rotating the pinion 23 by means of the operating handle I34 fixed in the bore I35 in the end of the shaft 22. While the chuck assembly C is being lowered the operator may either oscillate the chuck assembly or rotate the spark plug holder in order to start the pilot gauge 54 into the gap between the shell and central elec-- trodes of the spark plug and to cause the remaining feelers to follow therein. The operator must properly align the feelers with the shell electrodes and the electrodes with the rams before proceeding further. After they are aligned, the operator continues to move the feelers downwardly until they have reached their proper depth Within the gap and until the stop I36 carried by the adapter block 30 is in contact with the upper surface of the ram block 90 thereby preventing further downward movement of the feeler 53. At this point the pin of the lost motion connection between the piston 8I of the pump 82 has moved into contact with the bottom of its slot and the operator continues to move the plunger 20, yoke 59, and the ushrod 61 downwardly to operate the piston 8| of the pump 82 to force the pistons 95, 95 and 91 by fluid pressure inwardly and cause the rams 98, 99 and I00 to move inwardly and to bend the shell electrodes until the feelers 53 are clamped between the shell and central electrodes. The adjustable stop I31 carried by the yoke 68 contacts the upper surface of the jaw II of the main frame I9 when there is no plug in the machine and which prevents further downward movement of the operating handle, and is stopped by the rams against the electrodes, the pressure gauge I2I indicating the pull exerted on the handle.

The construction of the tool allows the spark plug to be shifted into exact proper alignment with the feelers andpermits the rams to exert force on the shell electrodes without imposing bending strain on the center electrodeof the spark plug. The feelers are constructed of sufficiently flexible material and so formed as to fit the radius of the center electrode and are so ground that they can be withdrawn from the gaps without disturbing the setting of the gaps.

Since the material of the spark plug electrodes is slightly resilient, the shell electrodes will spring back slightly after the ram are backed away and the feelers are therefore constructed thinner than the desired gap to allow the shell electrodes to be pressed in the distance they will spring back. The withdrawal of the rams and feelers is automatic when the operator raises the handle I34 or allows it to be raised by the action of the spring 84. The rams are assisted in their return to the inoperative position by the action of springs I06, I01 and I08 disposed between the ends of the bores 92, 93 and 94 and the inner faces of said pistons on the release of the hydraulic pressure in the tool. The vertical range of movement of the chuck assembly C is less than that of the plunger 20 because of the sliding action of the stud as previously described.

The tool may be adjusted by several means to accommodate spark plugs of a wide variety of sizes and makes; the time spent in changing the tool to fit one size of spark plug or another is inconsequential as comparedto the time saved by gapping a lot of the same sized plugs at one time.

In order to perform gapping operations on spark plugs having two or four shell electrodes instead of three as has been illustrated, the operator merely substitutes another ram block as shown in Figure 9 for the one shown in Figure 5. This ram block is constructed with two rams opposite each other and the gapping of a four electrode spark plug is done by rotating thespark plug degrees after the first opposing pair of electrodes are gapped. A spark plug having six equally spaced electrodes can similarly be gapped by double ram in three operations and so on.

The ram block shown in Figures 9, 10 and 11 is adapted for use in connection with spark plugs having two or more opposing shell electrodes and although the block is shown applied to a modified form of tool, it should be understood that it is also adaptable to that type of tool as shown in Figure 1 of the drawings.

The ram block 300 comprises a main body 30I having a bifurcated front portion 302 forming a recess 303 and a vertical bore 304, said bore is reduced as at 305 to accommodate the threaded end 306 of the pump cylinder 301. The bore 304 is closed at its top by means of a cap plug 3528, thereby providing a seal for the reservoir 309 formed by said bore. The bore of the pump cylinder communicates with the reservoir 309 by means of ports 3I0 formed through the walls of said pump cylinder. The cap plug 308 is centrally bored to permit the passage of the stem 3I I of the piston 3I2 which is in turn mounted in the pump cylinder 301. The block is further provided with two diametrically opposed diverging bores 32I connected to the bore of the pump by means of fluid passages 3I5 and 3I0. Pistons 3I1 are mounted in bores 32I and are provided with rams 3| 9 the ends of which are machined to form electrode forming dies 320. The rams 3I'9 extend inwardly through the bores 32I into the recess 303 formed in the bifurcated front portion of the main body 300. Springs 323 are disposed between the ends of the bores 32I and the inner enemas face of the pistons MEI madame eadant dimh i the pistons and rams inmetracted DOS BiQ 3 3 93 1 influenced :by :pressure ifrom :the pump i 31.- 15 711 outer .ends of the bores .321! prescaled by means ofplugs 324 whienare centrallyhandlin -t nn to receive the adjustable stops 25 adapted tp limit the outward movement-of the pistons 3L1. Stops 326 are provided in the :rront end pf the block 300 and are adapted'tocoactwith theslots 321 formed in the rams .319 for the-purpose of aligning the radii surfaces :Qf dies on the rams with the outer surface :of the-outer electrode ,of the spark plug.

While the piston; and the :ramsshowninffigure "are disposed perpendicularly with ,respect :gto the vertical aXiSDfqtheySDflik plug it ,shouldbe understood that said-pistons 1 and items could be disposed as-shownin igul'e 1,0 ;of-,the drawings in order to accommodateespark plugsihavingthree shell electrodes requiring angular adjustment thereof, and similarly the arrangement of the rams I and pistons shown in :ZEigure ,10 would ,be modified to accommodate g spark plugs; requiring the adjustment to be made perpendicularly {to thevertical axis of: the spark; plug.

In Figure 12 is shown the i=spark: plu ;;hol,der composed of thev hollow. tubular-body 33,0:with internal threads 33I and threaded; plug ;332. A steel ball 333 iscentered in the conical cavity334 and is a support for the hollow stem;335 pi arspark .plug insertedin the holder. .The body fiat-has; an annular shoulder =336=torest on. the bifurcated front portion. 3320f the gapping tool illustrated in Figures 9, wand-ll. ,Ihetubularbodyfiw may be providedrwith threads, (not ;S hOWn) j3Q fit the spark. plug. adapter 1 28=;of=l 'igures; 1, -2,;;-3,-,4 and 5,01 .otherwiseusedawith thegapnin $001;- of those figures without departing from .the scope and intent of the invention.

The sparkqplug holder '15 so constructedas to.

permit sparkplugs being gappedto-be pivoted; on thesteel ball 333 and to-yfloat-zaway from; the greater forcev that might be; exerted; uponfiither of the electrodes being gapped,.andzisgalsoadjust- .ablebymoving plug 332 to, accommodate plugs of reciprocatingly mounted on said base, hydraulic means mounted on. said base for actuatin said ram, and a hydraulic piston coacting with said plunger for providing pressure-to said-hydraulic means.

2. A gap settingtool for spark plugs having shell-and central electrodes comprising a base, a holder for a spark plug adjustablymounted on said base, a reciprocating plunger'mounted on said base substantially axially with said holder, a feeler gauge mounted" on the end'rof said plunger,

- a yoke attached tothemtherend ofsaid plunger,

an adjustablestopmto limit jthe travel of -said plunger, 2. cylindenmounted: on, said yoke, a; pis- ;ton reciprocalin;said;cylinder, an-electrode bend- -lnz: hydraulic ram,reclnrocatinzlysmountedzin a slumbe atta he to a base, ydra l nnections between said cylinder and said chamber, and an operating handle geared to said plungerwhereby said feeler gauge is limitedly inserted between the electrodes of the spark plug and said hydraulic ram and bends the shell electrode to form the gauged gap with one stroke of said handle.

3. n gap setting tool for spark plugs having shell and central electrodes comprising a base, ,a holder for-a spark plug adjustably mounted in ,an opening in said base, a plunger slidably mounted in achannel in said base axially with said holder, at least one feeler gauge mounted in a chuck on one end of said plunger and adapted tobe inserted between theelectrodes of the spark plug,,a;yoke attached to the other end of said plungenanadjustable stop to limit the travel of saidplunger, a rack gear cut into the side of said plunger engageable with a spur gear pinioned in said base, an operating handle attached to saidspurgear, at least one chamber in said base radial of said opening, a hydraulic ram mounted in. said chamber, a die attached-to each ram at the inner end adapted to fit the shell electrode, a hydraulic pump-operable by said yoke mounted .onsaidbaseand connecting means between said pumpand said chamber.

4. A gap setting tool for-spark plugs having shell and central electrodes comprising a base, a holder for a spark plug adjustablymounted in an opening in said base said holder having a conical cavity and a ball centered in said cavity adapted to fit the tubular stem. of a spark plug, .aplugslidably. mountedin achannel in said base axially with said holder, at least one feeler gauge mounted inachuck on one end of vsaid plunger andadapted to be inserted between the electrodes of the spark plug, a yoke attached to the other. end ofsaid plunger, an adjustable stop to limit thetravel of said plunger, a rack gear cut int o the side of said plunger engageable with a spui gearppinioned in said base, an operating handleattached to said spur gear, at least one chamber in said base radial of said opening, a hydraulicram mountedin saidchamber, a die attached to each ram at the inner end adapted to fit the shell electrode, a hydraulic pump oper- ,.able by said yoke mounted on said base, and connecting means betwecnsaid pump and said chamber.

,5. A apsettingtool for spark plugs having ,shelland central electrodes comprising means for adjustably mounting said spark plug on a base, 'feeler means for said spark plug movably mounted onsaid base and adapted for insertion between the electrodes of said spark plug, ram

:-References Cited in the file of this patent UNITED-STATES PATENTS lfiunnber Name Date 2,481,530 Oden Sept. 13. .1949 2 553,169 -Bretsch et a1. May 15, 1951 

